Haswell Overclocking

I'm a bit behind the times here, could someone please explain why only K series parts can be overclocked?

So, back in the early 2000s - as I'm sure most remember - we had a FSB /or HyperTransport bus, and a multiple of that number determined CPU speed, among other things.

Now fast forward today - I've been tuned out since Bulldozer's been floundering around - The NB is integrated into the CPU package along with a whole bunch of other "goodies" as the industry starts consolidating silicon, the faithful blue BIOS are gone, replaced with UEFI, and I hear 'consumer' Haswell parts can't be overclocked.

So, what's up? Is the base clock not adjustable? Does Intel lock the chips down more than simply setting a multiplier now?

I have many a found memory putting my E6300 through all sorts of abuse so I could have a processor that surpassed the stock frequency of even the might X6800. I learned much more about HVAC than any teenager should have had the attention span for, and what, now is all for naught? Can I no longer buy an entry-level CPU and through carefully doling out excessive amounts of cooling capacity and tweaking, have that chip operate beyond the binning level which Intel forced it?

It was almost noble, raising up all those poor little CPUs Intel and AMD said couldn't perform at higher performance bins. Granted, they still couldn't do it within their parent's respective set of tolerances, but I digress from my fairy tale.

There is no FSB to overclock anymore, so your only option is to bump the multiplier.

K chips have a fully unlocked multiplier, while non-K chips can be overclocked by 4 bins (400mhz) + their turbo.

You don't need a K chip if you just want a modest overclock. The i5-3470 is a good deal as it's often available for $180, and can be overclocked to 4ghz. That is a sweet spot for ivy bridge where the stock cooler can keep up with the heat. You can step up to the i5-3570K, but you will have to buy an aftermarket cooler to reach 4.3 - 4.5ghz. +$50 for +10%

So that's a pretty sad state of things - Though I guess for the industry as a whole, it makes sense - Intel's kinda taken overclocking and made it an internal process with the Turbo modes.

Kinda funny that stability is so highly effected by the BCLK, though - I'd like to see a technical write up from Ars, maybe even Anandtech, about why these parts are so twitchy. I imagine if it was solely a UEFI-imposed limit, some mobo maker would have enabled it by now - Asus hasn't made a name for the Rampage boards just because they're pretty.

Well, hopefully Piledriver parts will be a little more friendly - That, or I'll have to start benching ARM chips with DICE and LN2.

There's definitely some headroom for these parts, just bums me out it's limited to 'enthusiast' SKUs. The OC'ing community seems to have diminished quite a bit since the early 2000s. There's still a strong presence, but nothing like that tail end of the Ghz Race. It was like everyone got rid of their Athlon and P4 rigs, bought C2D/C2Q setups, and went for the same clocks that were the norm prior to the Core architecture release.

. It was like everyone got rid of their Athlon and P4 rigs, bought C2D/C2Q setups, and went for the same clocks that were the norm prior to the Core architecture release.

Given it was a similar process node, power density became a limiting factor, blah blah blah... but yeah, OC'ing is not like the old Celeron 300A days anymore... hell, I overclocked a fair number of Core 2 Quads and had significant trouble breaking the 3.2ghz barrier at a comfortable voltage, let alone hitting the full on 3.6ghz...

Definitely not the old placing a piece of tape over pin B21 days anymore.

There's definitely some headroom for these parts, just bums me out it's limited to 'enthusiast' SKUs.

I guess. A lot of the thrill for me on overclocking, first the 166mhz Pentium MMX to 208mhz (fastest Pentium ever, because I did it on the only board that allowed a 83mhz busspeed, which transfered to RAM and external L2 cache. And of course the PCI bus, probably helped texture transfer to my 3DFX card in fact), Celeron300a to 450mhz and pencil tricks on the Durons/Athlons, was that you were purchasing a cheap CPU, and making it perform like the expensive ones (well, the 166mhz MMX was expensive as well, just like to brag about it, because really, the undocumented 83mhz busspeed, and the fact that I had that as my first PC (came from the Amiga scene), was very special. That PC kicked ass for its time. Only one motherboard, and some very special RAM could do it)). (edit2: The special RAM I had was kinda weird. A friend of mine sold it to me, and I kinda knew he pilfered it from his place of work. But anyway, it was IBM branded EDO RAM rated for 66mhz. 16MB. And it ran at 83mhz, rock solid. And so did the additional 256KB of L2 cache I added to the Asus P/I-P55T2P4 motherboard. /CSB )

But of course, back then, CPU's were expensive, so you were "tricking the system with these "cheap" CPU's". So it's limited to "enthusiast' SKUs", true. But an i5-4670k costs 229USD at Newegg. Considering both the absolute cost, and the relative cost to the PC as a whole, that's not really a lot at all.

You can still get the thrill of letting people in on the Intel Celeron G530 for less than 50USD, so there's still cheating the system in that respect.

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If by "enthusiast' SKUs", you meant Intel removing features from the K model, then yeah, that's just annoying. I don't understand the point. I understand market segmentation. So Intel is trying to force people to purchase the non K version of the 4670 to get these features? But that CPU is cheaper. And the same is the case with the i7. I just don't get the point.

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edit:

Ah my video link was just pictures. I saw a video a while ago, so I just thought it was that. But all the same the commentary for the photo one mentions that the winner of the overclocking competetion did come in at ~7ghz at a live audience. So it is possible.

Kinda funny that stability is so highly effected by the BCLK, though - I'd like to see a technical write up from Ars, maybe even Anandtech, about why these parts are so twitchy. I imagine if it was solely a UEFI-imposed limit, some mobo maker would have enabled it by now - Asus hasn't made a name for the Rampage boards just because they're pretty.

It's not really that complicated. Many components besides the CPU rely on the BCLK setting for timing and are more prone to failing if you push them a little bit. You increase the BCLK, you're effectively overclocking the entire motherboard.

You can actually increase the BCLK directly but since everything is based off of it something fails usually before it is increased by 5%.

This is not true. Haswell has added BCLK strap options, where you can use a 100, 125 or 166 MHz BCLK strap while keeping everything else (i.e. PCIe bus, storage lanes, etc) in spec. That gives you the ability to a BCLK starting point, then adjust the same 5-10% up or down from there. Here are the basic strap options.